“Like I tell my five sisters, who don’t work very hard at all [to be fit]: Whatever you put in, you get out,” said Bundchen. “I’m not afraid of working hard at anything, whatever it is. I just always want to be the best that I can.”

Low-carb diets such as the Atkins and ketogenic diets promote rapid weight loss by inducing the body to burn fat for fuel, according to obesity expert Dr. Eric Westman, co-author of Keto Clarity.

Gisele quickly lost weight after her two pregnancies by following a low-carb organic diet. (Photo: Instagram)

In recent years, Bundchen’s diet has become about 80% vegetarian, said her personal chef, Allen Campbell. “A plant-based diet has the power to reverse and prevent disease,” said Campbell.

The anti-aging health and weight loss benefits of a vegan diet is no surprise to Dr. David Katz, director of Yale University’s Prevention Research Center.

Dr. Neal Barnard agrees. “Studies suggest that free radicals [toxic molecules that form in the body] contribute to aging,” Barnard wrote in his book, the 21-Day Weight Loss Kickstart. “A vegan diet, rich in fruits and vegetables, is full of antioxidants which help protect the body from damage by free radicals.”

Another celebrity vegan who lost weight with a vegan diet is Beyonce. The 5-foot-7 Beyonce who weighed 195 pounds while pregnant, lost 65 pounds six months after giving birth by following her trainer Marco Borges’ vegan diet, detailed in his bestseller, The 22 Day Revolution Diet.

As she did with her first pregnancy in 2009, Bundchen regained her svelte pre-baby body by watching her diet and doing yoga, martial arts and strength-training.